Why is walnut lumber graded lower than other hardwoods?

A few weeks ago I ordered 300 board feet of 12′, #1 common walnut from a wholesaler that I use on a regular basis. The customer that I ordered it for doesn’t mind knots, so #1 common, which is not the highest grade, is usually a fine choice – except in walnut. In the order, none of the boards looked very good, many were so crooked that I had to cut them in half to get a straight board, only a couple of the boards were over 7″ wide with a good number of them only 3-1/2″, and half of them looked like pallet wood.

They were painful to look at and painful to use. So painful, in fact, that out of the 300 bd. ft., I couldn’t find two boards that contained a 4″ x 7′ clear piece to finish up another order. Out of 300 bd. ft. of medium-grade walnut lumber, I couldn’t even find 5 bd. ft. of clear lumber. If that same stack was red oak instead of walnut, I would have been able to find those two pieces in the first layer of the stack. I may have even found the two pieces in one wide board, between the knots.

This wasn’t a randomly poor batch of walnut from a consistently good supply. Every time I order walnut, no matter which sawmill or distribution yard it comes from, the quality of the wood from any of the grades is always worse than I could imagine. The crazy thing is I know it is going to be bad going in, so I try to prepare myself for it, and I am still surprised when I see it. I do end up using it or selling it, explaining to my customers that it’s just the way walnut is, that it is graded by different rules and even though it doesn’t look great that it is indeed higher-grade lumber. I have a hard time with this explanation, but it is absolutely the truth – walnut is graded differently from other woods.

If you search the internet for the reason walnut is graded on a different scale, all you will find is something along the lines of, “Walnut is graded differently from other woods to make better use of this valuable resource.” This sounds like a quote from someone towing the company line and giving a politically correct answer, and it does nothing to explain why the grade is so different.

Big and straight walnut logs do exist. This one only got cut up into lumber because of bird peck marks that scarred the wood. Otherwise, it would have been shipped off to be sliced into veneer.

The only tidbit you will find that sounds like a real reason for the lower grade of walnut is that it is difficult to get good quality wood out of the walnut log supply. Most of the wording would make you believe that walnut trees don’t grow tall and straight and don’t get to a decent diameter, so there just isn’t anything good to pick from. This is partly true. There isn’t a lot of good quality logs to choose from, but it has almost nothing to do with the way walnuts grow – walnuts grow just as tall and straight and big as many reputable hardwoods. The real, full and complete truth is that, yes, the log supply doesn’t have many high quality logs, but it is because the high-quality logs never make it to the sawmill, it’s not that they don’t exist. I know that I find good-looking walnut logs all of the time, and I don’t have any special powers to find good logs.

When grading rough hardwood lumber, green, air-dried or kiln-dried, do you look at the worst side of the piece of lumber to determine the grade? Let's talk about that.

So, where are the good logs if they aren’t at the sawmill? They are sold to make veneer, which requires the best logs, and they are shipped overseas where walnut is viewed as even more valuable because it is a fancy import. And, since the demand for walnut is so high, even the “not the best, best” walnut logs are being shipped out and sliced into veneer. Species other than walnut are being sliced into veneer as well, but not in the same ratio when compared to the number of available trees. Walnut accounts for less than 1% of our forest, so there just aren’t as many logs to choose from and since almost every decent walnut log ends up anywhere but the sawmill, the odds of a good board ending up in the hands of a domestic customer are not good.

The situation is very obvious if you visit a higher production sawmill with a big supply of logs, where you will probably find three sorting categories for logs entering the yard. The largest pile of logs will be smaller diameter (14″ and less) and low-grade. The second biggest pile will be larger diameter logs (over 14″), but they will still be knotty and/or crooked. The last pile will be hidden in the back, away from the hustle and bustle of the sawmill where the best logs wait for the veneer buyer. These logs don’t have a chance of being cut into lumber because the sawmill can make just as much or more money selling the logs for veneer instead of wasting their time cutting, drying and selling them for lumber. If the sawmill can purchase a walnut log at $2 per board foot delivered to them and sell it for $3-$4 or more per board foot just for loading it on the veneer buyers truck, it makes no sense to touch it more than once.

So, the problem with walnut comes down to simple economics, supply and demand, that sort of thing. But why are the grades different? Obviously, “to make better use of this valuable resource,” meaning so sawmills can cut the lower grade logs that are available at a reasonable price and still sell them at a higher price. Walnut is that much in demand.

I did some research on walnut grading rules by contacting the National Hardwood Lumber Association (NHLA), which is responsible for implementing the current rules, thinking that the rules must have started out the same as other species (called standard grade) and then changed at some point based on the increasing demand for walnut. I found no time when the rules made any sort of abrupt change, so it appears that even though walnut may drift in and out of style, it has always been in demand and in relative short supply. Working with the chief lumber inspector, we went back to the 1920’s and even then walnut had special exceptions to make it easier to achieve a higher grade.

The differences in the grading rules for walnut may not sound so aggressive at first, but when you see them applied in real life, it is easy to see how lower-grade walnut can slide through in the higher-grade categories. Hardwood lumber is graded by the percentage of clear area in each board, with higher grades having fewer defects and more clear wood. The assumption is that the lumber is going to be cut down to make a finished product, so it can contain a specified number and minimum size of imaginary pieces (cuttings) that can be cut out of a single board.

The main differences between other hardwoods and walnut is in the additional number of cuttings allowed per board and the smaller size of the cuttings in each grade, meaning that you are allowed to cut a walnut board into more and smaller pieces to remove defects. The percentage yield of clear wood needs to be the same as other species in each grade, but the pieces can be much smaller. A great example is in the FAS (First and Seconds) grade of lumber, which is the highest grade in hardwoods. FAS lumber in walnut can have three cuttings instead of just the two in other hardwoods, and it can have shorter cuttings in lumber 8′ and longer, so the best walnut usually has a knot right in the middle of the board, where other species often won’t. That is great if you only need shorter pieces, but a real pain when you need 8′ of clear stock. You would be amazed how much FAS walnut you will have to go through to get a good amount of wide, clear and long stock, if you find it at all.
The white ring on the outside of this walnut log is the sapwood. It is considered a grading defect if not steamed.

The white ring on the outside of this walnut log is the sapwood. It is considered a grading defect if not steamed.

Another painful part of using commercially processed walnut is sapwood. Sapwood is the white wood on the outside of all logs, and it is a part of living life in the world of hardwoods, but since walnut heartwood is dark brown and contrasts so much, it is considered a defect (at least by the grading rules) and should be removed. Larger operations get around the sapwood issue by steaming their lumber to darken the sapwood. This is a separate operation, performed after the lumber is milled and before it is dried, that has moved walnut sapwood out of the defect category. In researching the NHLA grade books, walnut sapwood was not considered a defect, as long as it was steamed, as early as 1920.

Walnut with steamed sapwood may grade higher and look homogenous in a rough board, where it is difficult to discern sapwood from heartwood, but once the lumber is planed, the sapwood is often clearly visible, even though it has been darkened. This wouldn’t be the worst thing if it just kept a high-grade board with a touch of sapwood from being rejected, but it has allowed sawmills, while still meeting grade, to cut walnut lumber that may have up to a 100% sapwood face. No amount of steaming is going to make an all-sapwood walnut board look like anything more than an imitation of the original, and one that needs to be stained (with a walnut stain, crazy enough) to have a chance of looking acceptable.

Along with allowing the sapwood to be 100% useable introduces our good friend “Wane”. Wane isn’t a person, it is the area on the outside of a piece of lumber that is permissible to be non-existent and not reduce the footage of a board. It’s our favorite spot on the end of a 7″ wide board that only measures 5″ wide, when we really need that 7″. It comes into play now because lumber is being cut to the outer edge of the log since steamed sapwood is allowable. Sapwood and wane is allowable in other species as well, but in walnut it is just another obstacle in the way of producing a board that looks like it has no defects. A piece of walnut lumber can, and often will, have sapwood (as long as it is steamed), knots and wane and still make a high-grade.
At larger mills, walnut is rolled into a steamer like this one and steamed to darken the heartwood.

At larger mills, walnut is rolled into a steamer like this one and steamed to darken the heartwood.

To be clear on the sapwood issue, I am not against sapwood overall. I think the contrast between the sapwood and heartwood can be very pleasing. But some jobs require all dark heartwood or the customer would prefer all dark heartwood, and it is almost impossible to get it, even if you tried to specify it. Plus, while darkening the sapwood, steaming reduces the depth of the color in the heartwood, turning the entire board into a brown gray color instead of the deep-rich brown it is without steaming. Allowing steamed sapwood to not be a defect, just like the other special walnut grading rules is done, as they say, “to make better use of this valuable resource,” or maybe, just to sell more walnut.

I would argue that while there are written rules that clearly explain the different grades of walnut, it is unnecessary and extremely painful to have them different from other hardwoods. It is so painful, in fact, that both of my wholesalers told me that it wouldn’t break their hearts if they never sold another stick of walnut again, especially since they spend so much time listening to unhappy customers and dealing with a constant stream of returns. The point of having a grading system is so that everyone has a consistent and clear understanding of the products they are purchasing, and having such a great variation for one species does nothing but muddy the waters.

Again, it all comes back to economics. Sawmills can now pay a reasonable, if not low price (relatively speaking) for lower grades of walnut logs and sell the lumber as fast as they can cut it for a good margin. If sawmills had to move to cutting the high-grade logs to produce more truly high-grade lumber, the price of walnut, which is already high, would increase even more, probably to a point that it couldn’t be sold, at least that is what the custodians of the walnut lumber market would fear.

I personally think that the market would then just reflect what the real situation is. Just like gold, which is rare and very expensive, walnut lumber would go up in price commensurate with the demand because it wouldn’t be so easy to produce high-grade walnut. It already isn’t easy to produce high-grade walnut, it is just easier to sell it as high-grade walnut. The highest grade walnut might end up selling for twice the price it does now, but at least those paying for high-grade might actually get it.

There have been attempts to move walnut to standard grade, but they have fallen short with the walnut industry members voting to keep special rules for walnut in effect. The way the system is now keeps large walnut producers running their operations like they always have, which seems to be working, so there is little reason to change it. And, after some of my discussions with industry insiders, I found even one more reason walnut producers may want to stick to the status quo, and that is proprietary grades of walnut, meaning that producers can now sell “premium” or “super-premium” or whatever they want to call it walnut.

Since the highest grades of walnut are not that high, mills that specialize in walnut can now sell the clearest and straightest-grained walnut lumber for a premium (well beyond listed top prices) because no official grade exists for this product. They can ask higher prices and get it, as long as they deliver a product that they have the luxury of defining. It is a big win for the sawmill, but another loss for those on the other end just trying to purchase a good walnut board, because now a board that may have been beautiful and straight and perfect has even less of a chance to end up in a bundle of “high-grade” walnut. It just helps guarantee that your next FAS board won’t be clear and it will have a knot or three, probably right in the middle. Well, if nothing else, at least we are making better use of this valuable resource.

To be clear, I am not blaming any of my sawmilling friends for the current walnut situation. They are simply following the approved standards for the industry. I do, however, think walnut should be graded following the standard hardwood rules and without all of the exceptions. It reminds me a lot of playing a game with a first-grader that keeps changing the rules when they are not in their favor, and I just don’t want to play on that playground.

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About the Author:

Scott Wunder

From felling the trees through installation of the final piece Scott Wunder, owner of WunderWoods in St. Charles, MO, shares his woodworking knowledge with anyone that will talk to him about wood. Whether you want to learn about milling lumber or need help on a project, get your fill of woodworking infotainment at WunderWoods.com. Scott writes about all aspects of woodworking and specializes in finishing (mostly because no one else likes to sand).